I am about to start on a 14m2 patio with brick walls on 2 sides and brick edging on the other 2 sides. I have compacted the sub base (approx 40mm below the brick edging) and had planned to compact a 10:1 dry mix upto the level of the brick edging. In places the slabs (Indian sandstone) will overlap onto the brick edging whilst mainly being supported on the dry mix.
Should I mortar beneath the slabs only where they overlap the brick edging?
Should I mortar the entire slab?
Should I cover the brick edging with the dry mix and not mortar at all?
Any ideas / suggestions?
Laying on brick edging - Laying on brick edging
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InfAddict
- Posts: 61
- Joined: Mon Apr 05, 2004 8:58 pm
- Location: South Shields
Graham, are the brick edges intended to be a visible decorative edging or will the flags cover them completely? As you say 'overlap' I'm guessing that the flags will only partially cover the brick edging.
If that's the case then you need to consider what will stop the lateral movement of the flags. The brick walls should achieve this on your other edges, but have a look at the Laying to Free Edges page which explains several options available to you.
In a nutshell, you could use a mortared edge where you replace the edge most section of bedding with class II mortar and create a haunch covering the edge of the flag, therefore holding it in place. In your situation, it depends on your levels and if you've got enough depth for this - you mention a 40mm depth... if your bedding is 40-50mm that only leaves 0-10mm of mortar on top of the brick edging which isn't a lot.
The other option is using edge spots which are invisible and located under the edge flag. You basically scoop out two large spots of bedding mix and replace it will class II mortar. The flag hopefully adheres to this and they act as 'anchors' and hold the flag in place.
Anyway, Tony explains all this much better than me on the page I mention above.
As for a full mortar bed, this debate never ends. Tony and many other Brew Cabin regulars recommend a semi-dry mix every time for various reasons, including the fact you are less likely to create a mess and stain your shiny new sandstone. Some people argue that a wet mix is easier to lay with but the majority recommend a semi-dry mix, so I would go with that if I was you. There are situations where other bedding methods/materials could be considered, but for a patio the semi-dry is the best bet I think.
If that's the case then you need to consider what will stop the lateral movement of the flags. The brick walls should achieve this on your other edges, but have a look at the Laying to Free Edges page which explains several options available to you.
In a nutshell, you could use a mortared edge where you replace the edge most section of bedding with class II mortar and create a haunch covering the edge of the flag, therefore holding it in place. In your situation, it depends on your levels and if you've got enough depth for this - you mention a 40mm depth... if your bedding is 40-50mm that only leaves 0-10mm of mortar on top of the brick edging which isn't a lot.
The other option is using edge spots which are invisible and located under the edge flag. You basically scoop out two large spots of bedding mix and replace it will class II mortar. The flag hopefully adheres to this and they act as 'anchors' and hold the flag in place.
Anyway, Tony explains all this much better than me on the page I mention above.
As for a full mortar bed, this debate never ends. Tony and many other Brew Cabin regulars recommend a semi-dry mix every time for various reasons, including the fact you are less likely to create a mess and stain your shiny new sandstone. Some people argue that a wet mix is easier to lay with but the majority recommend a semi-dry mix, so I would go with that if I was you. There are situations where other bedding methods/materials could be considered, but for a patio the semi-dry is the best bet I think.
"I have a plan so cunning you could stick a tail on it and call it a weasel." - Edmund Blackadder III.